/**
 * 图片上传 公共组件
 */
<template>
  <div class="uploadWrapper">
    <vuedraggable class="vue-draggable" :class="{ single: isSingle, maxHidden: isMaxHidden }" v-model="imgList" tag="ul" draggable=".draggable-item" @start="onDragStart" @end="onDragEnd">
      <!-- 拖拽元素 -->
      <li v-for="(item, index) in imgList" :key="item + index" class="draggable-item" :style="{ width: width + 'px', height: height + 'px' }">
        <el-image :src="item" :preview-src-list="[item]"></el-image>

        <div class="shadow" @click="onRemoveHandler(index)">
          <i class="el-icon-delete"></i>
        </div>
      </li>
      <!-- 上传按钮 -->
      <el-upload slot="footer" ref="uploadRef" name="files" class="uploadBox" :style="{ width: width + 'px', height: height + 'px' }" :action="urlUpload" :headers="tokenHeader" accept=".jpg,.jpeg,.png,.gif" :show-file-list="false"
        :limit="limit" :before-upload="beforeUpload" :on-success="onSuccessUpload" :on-exceed="onExceed" multiple>
        <i class="el-icon-plus uploadIcon">
          <span class="uploading" v-show="isUploading">正在上传...</span>
          <span v-if="!isUploading && limit && limit !== 99 && !isSingle" class="limitTxt">最多{{ limit }}张</span>
        </i>
      </el-upload>
    </vuedraggable>
    <div class="el-upload__tip" slot="tip">{{ textExplain }}</div>
  </div>
</template>

<script>
import * as vuedraggable from "vuedraggable";
import * as validater from "@/utils/validater";
import * as lrz from "lrz"; // 前端图片压缩插件
import { getToken } from "@/utils/auth";
export default {
  name: "ImgUpload",
  components: { vuedraggable },

  data() {
    return {
      // headers: {},
      isUploading: false, // 正在上传状态
      isFirstMount: true, // 控制防止重复回显
      tokenHeader: { "X-Token": getToken() },
      urlUpload: process.env.VUE_APP_Base_Img_Url + "/api/sys/uploadgroup",
    };
  },
  props: {
    // 图片数据(图片url组成的数组) 通过v-model传递
    value: {
      type: Array,
      default() {
        return [];
      },
    },
    //说明文字
    textExplain: {
      type: String,
      default: "只能上传jpg/png文件，且不超过500Kb",
    },
    // 限制上传的图片数量
    limit: {
      type: Number,
      default: 10,
    },
    // 限制上传图片的文件大小(kb)
    size: {
      type: Number,
      default: 500,
    },
    // 是否是单图上传(单图上传就是已传图片和上传按钮重叠)
    isSingle: {
      type: Boolean,
      default: false,
    },
    // 是否使用图片压缩
    useCompress: {
      type: Boolean,
      default: false,
    },
    // 图片显示的宽度(px)
    width: {
      type: Number,
      default: 100,
    },
    // 图片显示的高度(px)
    height: {
      type: Number,
      default: 100,
    },
  },

  computed: {
    // 图片数组数据
    imgList: {
      get() {
        return this.value;
      },
      set(val) {
        if (val.length < this.imgList.length) {
          // 判断是删除图片时同步el-upload数据
          this.syncElUpload(val);
        }
        // 同步v-model
        this.$emit("input", val);
      },
    },
    // 控制达到最大限制时隐藏上传按钮
    isMaxHidden() {
      return this.imgList.length >= this.limit;
    },
  },

  watch: {
    value: {
      handler(val) {
        if (this.isFirstMount && this.value.length > 0) {
          this.syncElUpload();
        }
      },

      deep: true,
    },
  },

  mounted() {
    if (this.value.length > 0) {
      this.syncElUpload();
    }
  },

  methods: {
    /**
     * 创建唯一的字符串
     * @return {string} ojgdvbvaua40
     */
    createUniqueString() {
      const timestamp = +new Date() + "";
      const randomNum = parseInt((1 + Math.random()) * 65536) + "";
      return (+(randomNum + timestamp)).toString(32);
    },
    // 同步el-upload数据
    syncElUpload(val) {
      const imgList = val || this.imgList;
      this.$refs.uploadRef.uploadFiles = imgList.map((v, i) => {
        return {
          name: "pic" + i,
          url: v,
          status: "success",
          uid: this.createUniqueString(),
        };
      });
      this.isFirstMount = false;
    },

    // 上传图片之前
    beforeUpload(file) {
      this.isFirstMount = false;
      if (this.useCompress) {
        // 图片压缩
        return new Promise((resolve, reject) => {
          lrz(file, { width: 1920 })
            .then((rst) => {
              file = rst.file;
            })
            .always(() => {
              if (validater.validImgUpload(file, this.size)) {
                this.isUploading = true;
                resolve();
              } else {
                reject(new Error());
              }
            });
        });
      } else {
        if (validater.validImgUpload(file, this.size)) {
          this.isUploading = true;
          return true;
        } else {
          return false;
        }
      }
    },
    // 上传完单张图片
    onSuccessUpload(res, file, fileList) {
      // 这里需要根据你自己的接口返回数据格式和层级来自行修改
      if (res.code == 200) {
        // 判断接口上传成功
        if (this.imgList.length < this.limit) {
          // 未超限时，把接口返回的图片url地址添加到imgList
          // this.imgList.push(res.result[0].thumbnail);
          this.imgList.push(res.result[0].filePath);
        }
      } else {
        // 判断接口上传失败
        this.syncElUpload();
        this.$message({ type: "error", message: res.msg });
      }
      this.isUploading = false;
    },
    // 移除单张图片
    onRemoveHandler(index) {
      this.$confirm("确定删除该图片?", "提示", {
        confirmButtonText: "确定",
        cancelButtonText: "取消",
        type: "warning",
      })
        .then(() => {
          this.imgList = this.imgList.filter((v, i) => {
            return i !== index;
          });
        })
        .catch(() => { });
    },
    // 超限
    onExceed() {
      this.$refs.uploadRef.abort(); // 取消剩余接口请求
      this.syncElUpload();
      this.$message({
        type: "warning",
        message: `图片超限，最多可上传${this.limit}张图片`,
      });
    },
    onDragStart(e) {
      e.target.classList.add("hideShadow");
    },
    onDragEnd(e) {
      e.target.classList.remove("hideShadow");
    },
  },
};
</script>

<style lang="less" scoped>
:v-deep(.el-upload) {
  width: 100%;
  height: 100%;
}

// 上传按钮
.uploadIcon {
  width: 100%;
  height: 100%;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px dashed #c0ccda;
  background-color: #fbfdff;
  border-radius: 6px;
  font-size: 20px;
  color: #999;

  .limitTxt,
  .uploading {
    position: absolute;
    bottom: 10%;
    left: 0;
    width: 100%;
    font-size: 14px;
    text-align: center;
  }
}

// 拖拽
.vue-draggable {
  display: flex;
  flex-wrap: wrap;

  .draggable-item {
    margin-right: 5px;
    margin-bottom: 5px;
    border: 1px solid #ddd;
    border-radius: 6px;
    position: relative;
    overflow: hidden;

    .el-image {
      width: 100%;
      height: 100%;
    }
    .shadow {
      position: absolute;
      top: 0;
      right: 0;
      background-color: rgba(0, 0, 0, 0.5);
      opacity: 0;
      transition: opacity 0.3s;
      color: #fff;
      font-size: 20px;
      line-height: 20px;
      padding: 2px;
      cursor: pointer;
    }
    &:hover {
      .shadow {
        opacity: 1;
      }
    }
  }
  &.hideShadow {
    .shadow {
      display: none;
    }
  }
  &.single {
    overflow: hidden;
    position: relative;

    .draggable-item {
      position: absolute;
      left: 0;
      top: 0;
      z-index: 1;
    }
  }
  &.maxHidden {
    .uploadBox {
      display: none;
    }
  }
}
// el-image
.el-image-viewer__wrapper {
  .el-image-viewer__mask {
    opacity: 0.8;
  }
  .el-icon-circle-close {
    color: #fff;
  }
}
.el-upload__tip {
  margin-left: 40px;
}
</style>

